The present invention pertains to the measurement of the velocity of fluid flows and was developed originally for use in a device which measures the velocity of fluid flow by photographing the displacements of fine (micron sized) particles using multiple exposures from a pulsed laser. The primary background area is, therefore, instrumentation for fluid flow measurement. More generally, the invention pertains to any image processing problem in which the displacements of many discrete images are to be measured, including the motion of solids.
For specific background material, reference may be made to co-pending application Ser. No. 738,775 now U.S. Pat. No. 4,729,109 assigned to the assignee of the present invention. The disclose of that application is incorporated herein by reference. In that application a method and apparatus for measuring the displacements of particle images for multiple exposure velocimetry are described. In particular, the method and apparatus involves the provision of a source of compact images and a specialized operation of compressing those images, which entails integrating the image intensity in the X and Y directions to produce respective electrical signals corresponding to the images. The system further involves analyzing the electrical signals resulting from the separate one dimensional compressions so as to determine the X and Y image displacements respectively.
The complete description of the system of the forenoted co-pending application is incorporated herein by reference as one example of a system which can be improved by inclusion of the present invention. However, the present invention is not limited to being incorporated only into the system of that co-pending application, but is of general applicability to velocimetry systems.